| DQ 19.1 |
Why is it difficult to measure the fitnesses of different alleles?
|
| DQ 19.2 |
Suppose that we find that an allele is fitter than average, that is, it leaves more copies than average in the next generation.
i) How can we find if the allele itself causes increased fitness, rather than just being associated with other factors that cause the increase?
ii) Natural selection itself faces this difficulty, in picking out alleles that increase fitness. How does adaptation in nature overcome this problem?
|
| DQ 19.3 |
Larger flowers attract more pollinators and therefore pollinate more flowers themselves. Yet, despite this selection, flower size remains constant from year to year. What might explain this failure to respond to selection? How could you distinguish between alternative explanations?
|
| DQ 19.4 |
Selection can be detected by comparing patterns of variation with those expected under the neutral theory. Various indirect methods for detecting selection were classified on page 531. Draw up a table that classifies the methods discussed later in Chapter 19.
|
| DQ 19.5 |
Often, there are more rare alleles in a population than expected under the neutral theory (see, e.g., Fig. 19.14). What could explain this excess?
|
| DQ 19.6 |
Explain how variation in levels of nucleotide diversity along the genome can be used to detect selection.
|
| DQ 19.7 |
A key achievement of molecular biology was to show how the DNA sequence codes for amino acid sequence. What other functions, besides coding for proteins, does the DNA sequence carry out?
|
| DQ 19.8 |
Studies of twins have suggested that a substantial fraction of human fitness variation is inherited (p. 548). What might the implications be if this is so?
|
| DQ 19.9 |
What limits natural selection? NOTE 19A
|
